A Review of the Effect of the Chemical Composition of the Atmosphere on the Dry Gas Constant over Multiple Time Scales

Dias, Nelson Luís

doi:10.1590/0102-77863610002

Acessibilidade / Reportar erro

Brasil

Revista Brasileira de Meteorologia

Español English

Brasil

Español English

sumário « anterior atual seguinte »

Sumário

Artigo • Rev. bras. meteorol. 36 (2) • Apr-Jun 2021 • https://doi.org/10.1590/0102-77863610002 copy

A Review of the Effect of the Chemical Composition of the Atmosphere on the Dry Gas Constant over Multiple Time Scales

Authorship SCIMAGO INSTITUTIONS RANKINGS

Abstract

The calculation of the dry-air constant depends on the concentrations of the main atmospheric constituents. The variation in N₂, O₂ and CO₂ concentration over the last 23 million years has a small, but calculable, effect on the value of the constant. For modern times, a comparison is made between some estimates in the literature, and a heuristic adjustment of the concentrations of the main components is proposed, in order to account for the CO₂ increase during the last decades; a confidence interval for the value of the constant is also estimated. Over longer time scales two periods are analyzed: the Christian era (Period I), and the last 23 Ma (Period II). It is found that the increase in CO₂ that started with the Industrial Revolution has an impact on the constant over Period I, but that changes in the constant during Period II are caused by increasing O₂ levels.

Keywords:
gas constant; dry air; chemical composition of the atmosphere

Gás	$M_{i}$	$x_{i}$	$x_{i}$	$x_{i}$	$x_{i}$	$x_{i}$
	$({gmol}^{- 1})$	IRI	COE	WAL	WIK	PRE
N₂	28,0134	0,78090000	0,78084000	0,78084000	0,78084000	0,78078700
O₂	31,9988	0,20950000	0,20947600	0,20946000	0,20946000	0,20943200
Ar	39,948	0,00930000	0,00934000	0,00934000	0,00934000	0,00934000
CO₂	44,0095	0,00030000	0,00031400	0,00037900	0,00040700	0,00041390
Ne	20,1797	–	0,00001818	0,00001818	0,00001818	0,00001818
He	4,002602	–	0,00000524	0,00000524	0,00000524	0,00000524
CH₄	16,0425	–	0,00000200	0,00000170	0,00000180	0,00000170
Kr	83,798	–	0,00000114	–	0,00000114	0,00000110
H₂	2,01588	–	0,00000055	0,00000056	0,00000055	0,00000055
N₂O	44,0128	–	–	0,00000031	–	0,00000033
Xe	131,293	–	0,000000087	–	–	–
Soma		1,00000000	0,99999715	1,00004499	1,00007391	1,00000000

Fonte	$M_{s}$ (rep)	$M_{s}$ (calc)	$R_{s}$ (rep)	$R_{s}$ (calc)
	$({gmol}^{- 1})$	$({gmol}^{- 1})$	$({Jkg}^{- 1} K^{- 1})$	$({Jkg}^{- 1} K^{- 1})$
IRI	28,9640	28,9641	287,0500	287,0607
COE	28,9644	28,9644	287,0580	287,0569
WAL	28,9700	28,9667	287,0000	287,0484
WIK	–	28,9680	–	287,0436
PRE	–	28,9659	–	287,0429

N₂	O₂	Ar	CO₂	Ne	He	CH₄	Kr	H₂	N₂O
5	5	5	6	8	8	7	8	8	8

Sociedade Brasileira de Meteorologia Rua. Do México - Centro - Rio de Janeiro - RJ - Brasil, +55(83)981340757 - São Paulo - SP - Brazil
E-mail: sbmet@sbmet.org.br

Acompanhe os números deste periódico no seu leitor de RSS

[1] Autor de correspondência: Nelson Luís Dias, nelsonluisdias@gmail.com.